Pregnancy - Me and my girlfriend had sex about two weeks ago?

Me and my girlfriend had sex about two weeks ago. We first put it in without a condom then after a few min we put one on. I didnt feel like i pre-cummed or anything when it was in without the condom. Now we are worried cause we cant remember the last time she had her period and her breasts are sore. I feel like she isnt but want a second opinion. Thanks